Restaurant operators were feeling better about things in November, according to the National Restaurant Association’s latest Restaurant Performance Index.

Sales gains and increasing optimism sent the index, which gauges the outlook for the industry based on feedback from restaurant operators, to its highest level in five months, 100.6. A score above 100 indicates expansion in the industry.

Restaurant operators reported the strongest same-store sales in November in more than four years, with half of operators saying sales were up from the year before. Only 28 percent said sales had declined.

Similarly, 41 percent of operators said more customers were coming into restaurants in November than they were a year ago, and only 32 percent said customer traffic was down.

Restaurants raised their expectations for the coming months, with 41 percent saying they expect higher year-over-year sales in six months, compared with 35 percent who said so in October. Only 12 percent of restaurant operators surveyed expect their sales to be lower.

Twenty-seven percent of operators said the economy would improve over the next six months, about the same as October. Only 16 percent said they expect the economy to get worse; in October, 22 percent said it would get worse.